This is Book Three in the Lilith Mercury Series.
Lilith's reputation as the best in the business has spread, and not just to the lycanthrope population. She's been hired to find the original vampire. The vamps want what everyone else wants, equality. However, she will soon realize that the original vampire isn't simply out for blood, or the return of rights to his people ... he wants Lilith too.
Warning: This book contains graphic violence, graphic language, and sex with BDSM elements including autoerotic asphyxiation.